NEW TO BOATING

[xStefanox]

Hi everyone. I'm sorry if this has been in a previous discussion , but I'm running out of time and weather and would really like to take my family boating. Ok so I have a 1991 SUNRAY PRELUDE with a 230/V8 ( I believe a 305) I just bought this boat and dumped it into the lake to see how it runs. It starts fine and you need to keep it at about 1500 rpm to keep running , and has no problem of revving up to 6000 rpm. I know it's not good for that but you will understand, I hope. When I try to go for neutral to drive , if I don't Rev it and switch it fast enough it will die. When I do get it in drive, I can have it full throttle and the carburetor will cough and pop and the boat will only do 5mph at 2000 rpm. I put seafoam in the gas tank and cleaned out fuel filter on the rochester carburetor. It has been replaced with a plastic one not the cardboard ones. I put fresh high octane fuel in and the problem still persists. Is there someone out there that can help me out , and hopefully earn some brownie points with my family?
Sincerely
Lost.....

 

[achris]

Sounds like a serious carb problem. Start by pulling the carb off, stripping and cleaning... Put a new set of gaskets and diaphrams in and reset all the adjustments and put it back on. Do a full tune and I think you'll find the engine is a lot better.

Chris....

 

[Rick Stephens]

If the carb is popping it is probably timing.

There is a switch on the linkage that is supposed to momentarily kill the ignition when you take it out of gear - a function of gears that have angled dogs to them and unloading the drive train to get it out of gear - if your lower shift cable is sticky it will kill the engine when you shift into gear as well. I'm afraid the best way is reading a lot of the adults only section to get a more in depth feel for how this works. Brutally simple once you understand it. This may be what is causing your engine to die when you put it into gear.

If the engine is running bad enough then that alone would account for the problem - water in the fuel, ignition issue, valves, compression, gunked up plugs, whatever.

Rick

 

[xStefanox]

If the carb is popping it is probably timing.

There is a switch on the linkage that is supposed to momentarily kill the ignition when you take it out of gear - a function of gears that have angled dogs to them and unloading the drive train to get it out of gear - if your lower shift cable is sticky it will kill the engine when you shift into gear as well. I'm afraid the best way is reading a lot of the adults only section to get a more in depth feel for how this works. Brutally simple once you understand it. This may be what is causing your engine to die when you put it into gear.

If the engine is running bad enough then that alone would account for the problem - water in the fuel, ignition issue, valves, compression, gunked up plugs, whatever.

Rick
Achris I called a local shop , and the first thing they said was the carburetor. Now I just pulled the plugs out of the moto, and 6 out of the 8 plugs were BLACK and MOIST. the two that were not too black ( brown in color) came out dry and we're out of cylinder #'s 6&5. The wires on the boat are brand new. Someone also told me that there is a module in the cap of the distributor that could also be the problem??? Does this make any sense to you guys?

 

[xStefanox]

Achris I called a local shop , and the first thing they said was the carburetor. Now I just pulled the plugs out of the moto, and 6 out of the 8 plugs were BLACK and MOIST. the two that were not too black ( brown in color) came out dry and we're out of cylinder #'s 6&5. The wires on the boat are brand new. Someone also told me that there is a module in the cap of the distributor that could also be the problem??? Does this make any sense to you guys?

 

[achris]

That module in the distributor is the ignition sensor. It tells the ignition amplifier when to fire the spark. EXTREMELY unlikely to be the cause of your problems. Black sooty plugs ARE a symptom of a rich carb.... Unless the black moist is oil, in which case you have bad rings or valve guides....

Chris.....

 

[xStefanox]

By having " bad rings, or valve guides" would that cause the boat to a t the way it is , or do you think it's the carburetor still? When I have the muffs on the out drive, there is no smoke indicating burning oil. I do want to mention that when it's hooked up to the muffs , I can have it idling and I still have to move the throttle lever quickly to put it in drive , and as I increase the throttle , I can get the rps up but if it's in the water it's a whole different scenario. The prop that's on it is a QUICKSILVER MIRAGE 15-1/4" 19P.

 

[Rick Stephens]

Bad rings will show up in a compression test. Valve guides usually show up in a vacuum test. Those are fairly easy to test out. Simplest is smell the plugs, if the wet ones smell like oil then it is time to do the compression and vacuum tests.

Meanwhile, when you have a problem like this, rebuilding the carb and checking the timing are always in order. Go to basics and check everything. Are the plugs the correct ones? Do the plug wires look in good shape? Is the timing spot on according to the book? Is the lower shift cable silky smooth when hand shifting it while disconnected from the engine end linkage?

Be methodical and check it all. If the mechanics who worked on the boat have been of hit or miss abilities, then more than one thing can be off. A couple of small things can keep your boat from running safely. If you need help knowing what should be the right settings or how to adjust, ask away here. And read up in the Adults Only and DIY sections at the top of the forums. Lots of accumulated knowledge here.

Rick

 

[xStefanox]

The plugs that I pulled from my boat are a NGK YR5 V-POWER do you know if this is the right plug as I do not have a manual for the boat. And yes I will get myself one.
Thanks

 

[Rick Stephens]

You can peruse the factory Mercruiser manual online at http://boatinfo.no/lib/library.html Great resource - the original factory manuals are a must to use. The online version isn't as nice as having a hardcopy but is a lot less expensive and available. I think you need manual #15.

The aftermarket manuals are only good for startin fires and propin up a chair with a missin wheel.

Plugs listed in the Merc manual are AC-MR43T for all small blocks 5.0 through 5.7L - which I recommend AC plugs in GM motors. The YR5 is listed as a similar alternate plug on my chart. No idea if it is a different temp range or not. Can't go wrong with the AC MR43T.


Rick

 

[xStefanox]

Would the choke have anything to do with the bogging?I mean if I try to give it full throttle , the choke was opening and closing while full throttle and not allowing all 4 barrels to open up. I believe it would dump more fuel than it can ignite

 

[xStefanox]

Just a thought!

 

[xStefanox]

I just ordered the plugs and will be coming today. Will let you know results

 

[Rick Stephens]

You sure that's the choke and not just the secondary? Choke is only on the smaller 2 barrels.

 

[Bondo]

Would the choke have anything to do with the bogging?I mean if I try to give it full throttle , the choke was opening and closing while full throttle and not allowing all 4 barrels to open up. I believe it would dump more fuel than it can ignite

Ayuh,.... Welcome Aboard,..... Ya gotta pull the carb, 'n rebuild it, or replace it,....

'91 must be the last year, or nearly so for the Quadra-jet,.... the Merc/ Weber AFB clone came out right along that time,....

 

[xStefanox]

So I put the new plugs in and brought it to the lake, and needless to say, it still runs like ****! I have a rochester carburetor that came off a car with a 305. Is there anything I have to do to it to make it run on my boat? Meaning vacume lines need to be plugged?let me note that on the new carb it had electronic choke, it was removed by the mechanic because he doesn't drive it in the winter. I'll be switchin carbs in the morning and hopefully that might solve my problem. If not I'll be bringing this to the marina to have it looked at and hopefully they can diagnose this whole problem

 

[xStefanox]

A mechanic gave me a carburetor that was on his nova. It's a rochester quadrajet but obviously set up for a car. He also HAD a electronic choke which he disconnected as he didn't drive the vehicle in the winter so there fore didn't need the choke. ANYWAYS to get where going is there anything I would have to change or do to the new carb to work with my boat? I'm just wondering about vacume lines and such.

 

[xStefanox]

Ayuh,.... Welcome Aboard,..... Ya gotta pull the carb, 'n rebuild it, or replace it,....

'91 must be the last year, or nearly so for the Quadra-jet,.... the Merc/ Weber AFB clone came out right along that time,....

 

[Bondo]

Ayuh,..... An automotive carb on a boat motor is a Bomb,.... Don't do it,.....

Carbs, Must be Marine rated,.....

 

[xStefanox]

What is the difference between marine and automotive carburetors